Liquid crystal display panel

ABSTRACT

A liquid crystal display panel including pixels, wherein at least one of the pixels includes a first sub-pixel charged with a first voltage and a second sub-pixel charged with a second voltage lower than the first voltage, a first substrate including a first sub-pixel electrode of the first sub-pixel and a second sub-pixel electrode of the second sub-pixel, a first alignment layer aligned in first and second directions in each of the first and second sub-pixels, a second alignment layer aligned in third and fourth directions in each of the first and second sub-pixels to form a plurality of domains in each of the first and second sub-pixels, and a liquid crystal layer disposed between the first and second alignment layers, wherein the first sub-pixel electrode includes a plurality of slits formed substantially parallel to a liquid crystal alignment direction in each of the domains of the first sub-pixel electrode.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Korean Patent Application No.10-2010-0128411 filed on Dec. 15, 2010, the disclosure of which isincorporated by reference herein in its entirety.

BACKGROUND

1. Technical Field

The present invention relates to a liquid crystal display panel. Moreparticularly, the present invention relates to a liquid crystal displaypanel that has improved side visibility and pixel response speed.

2. Discussion of the Related Art

In general, in a liquid crystal display, a voltage is applied to aliquid crystal layer to control a transmittance of light passing throughthe liquid crystal layer, thereby displaying a desired image. The liquidcrystal display may be classified as a twisted nematic type liquidcrystal display, a horizontal electric field type liquid crystaldisplay, or a vertical alignment type liquid crystal display.

The vertical alignment type liquid crystal display aligns liquid crystalmolecules such that their long axes are perpendicular to a displayscreen of the vertical alignment type liquid crystal display in theabsence of an electric field.

The liquid crystal molecules are aligned by using alignment filmsmanufactured with a rubbing method or a light alignment method. However,liquid crystal molecules between such alignment films are subject tomisalignments in a no electric field state. These misalignments maylessen the side viewing angle and degrade the pixel response speed ofthe vertical alignment type liquid crystal display. Accordingly, thereis a need for a liquid crystal display with improved side visibility andpixel response speed.

SUMMARY

According to an exemplary embodiment of the present invention, a liquidcrystal display panel includes a plurality of pixels, wherein at leastone of the pixels includes a first sub-pixel charged with a firstvoltage and a second sub-pixel charged with a second voltage lower thanthe first voltage. The liquid crystal display panel includes a firstsubstrate including a first sub-pixel electrode of the first sub-pixeland a second sub-pixel electrode of the second sub-pixel. The liquidcrystal display panel includes a first alignment layer disposed on thefirst substrate and aligned in a first direction and a second directionin each of the first and second sub-pixels, a second substrate facingthe first substrate, a second alignment layer disposed on the secondsubstrate and aligned in a third direction and a fourth direction ineach of the first and second sub-pixels to form a plurality of domainsin each of the first and second sub-pixels, and a liquid crystal layerdisposed between the first alignment layer and the second alignmentlayer.

The first sub-pixel electrode includes a plurality of slits formedsubstantially parallel to a liquid crystal alignment direction in eachof the domains of the first sub-pixel electrode.

The pixels comprise first pixel displaying a red color, a second pixeldisplaying a green color, and a third pixel displaying a blue color, andthe at least one pixel is the third pixel.

Each of the first and second sub-pixel electrodes comprises first,second, third, and fourth domains and the liquid crystal alignmentdirections of the first to fourth domains of the first sub-pixelelectrode are different from each other, and a liquid crystal alignmentdirection in each of the first to fourth domains of the second sub-pixelelectrode are different from each other.

The slits comprise first, second, third, and fourth slits respectivelycorresponding to the first, second, third, and fourth domains of thefirst sub-pixel electrode, and each of the slits is formed substantiallyparallel to the liquid crystal alignment direction of its correspondingdomain.

The first sub-pixel electrode comprises a first fringe field area formedalong edges of the first domain and having an L shape, a second fringefield area formed along edges of the second domain and having an L shapethat is rotated 90 degrees in the counter-clockwise direction from theposition of the L shape in the first domain, a third fringe field areaformed along edges of the third domain and having an L shape rotated 90degrees in the clockwise direction from the position of the L shape inthe first domain, and a fourth fringe area formed along edges of thefourth domain and having an L shape rotated 180 degrees in thecounter-clockwise direction from the position of the L shape in thefirst domain.

The first, second, third, and fourth slits are provided in the first,second, third, and fourth fringe field areas, respectively.

The first sub-pixel electrode comprises a first fringe field area formedalong an edge of the first domain, a second fringe field area formedalong an edge of the second domain, a third fringe field area formedalong an edge of the third domain, and a fourth fringe field area formedalong an edge of the fourth domain, and the first, second, third, andfourth slits are formed along the edges of the first sub-pixel electrodeexcept where the first, second, third, and fourth fringe field areas areformed.

Each of the slits has a length of about 10 percent of a width of thefirst sub-pixel electrode.

An entire area in which the slits are formed is about 10 percent toabout 90 percent of an entire area of the first sub-pixel electrode.

The first and second pixels each include a first sub-pixel charged withthe first voltage and a second sub-pixel charged with the secondvoltage, and a voltage ratio of the second voltage to the first voltagein the third pixel is equal to or different from a voltage ratio of thesecond voltage to the first voltage in each of the first and secondpixels.

The voltage ratio of the second voltage to the first voltage in thethird pixel is larger than the voltage ratio of the second voltage tothe first voltage in the second pixel, and the voltage ratio of thesecond voltage to the first voltage in the first pixel is equal to orsmaller than the voltage ratio of the second voltage to the firstvoltage in the second pixel.

The voltage ratio of the second voltage to the first voltage in thefirst pixel is about 0.59 to about 0.845, the voltage ratio of thesecond voltage to the first voltage in the second pixel is about 0.6 toabout 0.85, the voltage ratio of the second voltage to the first voltagein the third pixel is about 0.61 to about 0.9.

The first and second pixels each include first and second sub-pixelelectrodes disposed on the first substrate, and the first sub-pixelelectrode of each of the first, second, and third pixels has a sizedifferent from a size of the second sub-pixel electrode of each of thefirst, second, and third pixels, respectively, and an area ratio of thesecond sub-pixel electrode to the first sub-pixel electrode is equal toor different from an area ratio of the second sub-pixel electrode to thefirst sub-pixel electrode in each of the first and second pixels.

The area ratio of the second sub-pixel electrode to the first sub-pixelelectrode in the third pixel is larger than the area ratio of the secondsub-pixel electrode to the first sub-pixel electrode in the secondpixel.

The area ratio of the second sub-pixel electrode to the first sub-pixelelectrode in the third pixel is about 1:1.1 to about 1:3.5, and the arearatio of the second sub-pixel electrode to the first sub-pixel electrodein the second pixel is about 1:1 to about 1:2.5.

Each of the first alignment layer and the second alignment layercomprises a polymer material in which decomposition, dimerization, orisomerization occurs when irradiated by a light.

According to an exemplary embodiment of the present invention, a liquidcrystal display panel includes a plurality of pixels, wherein at leastone of the pixels includes a first sub-pixel charged with a firstvoltage and a second sub-pixel charged with a second voltage lower thanthe first voltage. The liquid crystal display panel includes a firstsubstrate including a first sub-pixel electrode of the first sub-pixeland a second sub-pixel electrode of the second sub-pixel, a secondsubstrate facing the first substrate, and a liquid crystal layerdisposed between the first substrate and the second substrate.

Each of the first sub-pixel electrode and the second sub-pixel electrodeincludes at least two domains having different liquid crystal alignmentdirections, and the first sub-pixel electrode includes a plurality ofslits in at least one of its domains. The slits are formed substantiallyparallel to the liquid crystal alignment direction of the domain inwhich it is formed.

The pixels comprise a first pixel displaying a red color, a second pixeldisplaying a green color, and a third pixel displaying a blue color, andthe at least one pixel is the third pixel.

The first and second pixels each include a first sub-pixel charged withthe first voltage and a second sub-pixel charged with the secondvoltage, and the voltage ratio of the second voltage to the firstvoltage in the third pixel is larger than the voltage ratio of thesecond voltage to the first voltage in the second pixel, and the voltageratio of the second voltage to the first voltage in the first pixel isequal to or smaller than the voltage ratio of the second voltage to thefirst voltage in the second pixel.

The first and second pixels each include first and second sub-pixelelectrodes disposed on the first substrate, and the area ratio of thesecond sub-pixel electrode to the first sub-pixel electrode in the thirdpixel is larger than the area ratio of the second sub-pixel electrode tothe first sub-pixel electrode in the second pixel.

According to an exemplary embodiment of the present invention, a liquidcrystal display panel, comprises: a plurality of pixels, wherein theplurality of pixels include first and second pixels displaying adifferent color from each other, each of the first and second pixelsincluding a first sub-pixel and a second sub-pixel, and each of thefirst and second sub-pixels includes a plurality of domains, the domainshaving a different liquid crystal alignment direction from each other,wherein the first sub-pixel of the first pixel includes a firstsub-pixel electrode having a plurality of slits disposed along an edgeof the first sub-pixel electrode.

A voltage ratio of a voltage applied to a second sub-pixel electrode ofthe first pixel and a voltage applied to the first sub-pixel electrodeof the first pixel is greater than a voltage ratio of a voltage appliedto a second sub-pixel electrode of the second pixel and a voltageapplied to a first sub-pixel electrode of the second pixel.

An area ratio of a second sub-pixel electrode of the first pixel to thefirst sub-pixel electrode of the first pixel is greater than an arearatio of a second sub-pixel electrode of the second pixel to a firstsub-pixel electrode of the second pixel.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features of the present invention will become moreapparent by describing in detail exemplary embodiments thereof withreference to the accompanying drawings in which:

FIG. 1 is a plan view showing a pixel part of a liquid crystal displaypanel according to an exemplary embodiment of the present invention;

FIG. 2 is an equivalent circuit diagram showing a first sub-pixel and asecond sub-pixel of FIG. 1, according to an exemplary embodiment of thepresent invention;

FIG. 3 is a cross-sectional view taken along a line It of FIG. 1;

FIG. 4A is a plan view showing alignment directions of a first alignmentlayer according to an exemplary embodiment of the present invention;

FIG. 4B is a plan view showing alignment directions of a secondalignment layer according to an exemplary embodiment of the presentinvention;

FIG. 4C is a plan view showing a first sub-pixel and a second sub-pixelaccording to an exemplary embodiment of the present invention;

FIG. 5A is a plan view showing alignment directions of a first alignmentlayer according to an exemplary embodiment of the present invention;

FIG. 5B is a plan view showing alignment directions of a secondalignment layer according to an exemplary embodiment of the presentinvention;

FIG. 5C is a plan view showing a first sub-pixel and a second sub-pixelaccording to an exemplary embodiment of the present invention;

FIG. 6 is a graph showing side gamma curves of two liquid crystaldisplay panels;

FIG. 7 is a graph showing side gammas curve of first, second, and thirdpixels displaying red, green, and blue colors, respectively;

FIG. 8 is a graph showing x-coordinate values and y-coordinate values oftwo white color coordinate values;

FIG. 9 is a graph showing a variation of side gamma curves according toa voltage ratio of a second sub-pixel electrode to a first sub-pixelelectrode, according to an exemplary embodiment of the presentinvention;

FIG. 10 is a graph showing a variation of gamma curves according to anarea ratio of a second sub-pixel electrode to a first sub-pixelelectrode, according to an exemplary embodiment of the presentinvention;

FIG. 11 is a plan view showing a pixel part of a liquid crystal displaypanel according to an exemplary embodiment of the present invention;

FIG. 12A is a plan view showing a first sub-pixel electrode of a thirdpixel according to an exemplary embodiment of the present invention;

FIG. 12B is a plan view showing a first sub-pixel electrode of a thirdpixel according to an exemplary embodiment of the present invention;

FIG. 13 is a graph showing a liquid crystal response characteristic of afirst pixel and a third pixel, according to an exemplary embodiment ofthe present invention;

FIG. 14 is an equivalent circuit diagram showing a pixel in a liquidcrystal display panel according to an exemplary embodiment of thepresent invention;

FIG. 15 is a plan view showing an array substrate including the pixelshown in FIG. 14, according to an exemplary embodiment of the presentinvention;

FIG. 16 is an equivalent circuit diagram showing a pixel in a liquidcrystal display panel according to an exemplary embodiment of thepresent invention;

FIG. 17 is a plan view showing an array substrate including the pixelshown in FIG. 16, according to an exemplary embodiment of the presentinvention;

FIG. 18 is an equivalent circuit diagram showing a pixel in a liquidcrystal display panel according to an exemplary embodiment of thepresent invention; and

FIG. 19 is a plan view showing an array substrate including the pixelshown in FIG. 18, according to an exemplary embodiment of the presentinvention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Exemplary embodiments of the present invention will be described morefully hereinafter with reference to the accompanying drawings. However,the present invention may be embodied in various different ways andshould not be construed as limited to the exemplary embodimentsdescribed herein.

It will be understood that when an element or layer is referred to asbeing “on,” “connected to” or “coupled to” another element or layer, itcan be directly on, connected or coupled to the other element or layeror intervening elements or layers may be present. Like numbers may referto like elements throughout the specification and drawings.

FIG. 1 is a plan view showing a pixel part of a liquid crystal displaypanel according to an exemplary embodiment of the present invention, andFIG. 2 is an equivalent circuit diagram showing a first sub-pixel and asecond sub-pixel of FIG. 1, according to an exemplary embodiment of thepresent invention.

Referring to FIG. 1, a liquid crystal display panel 400 includes aplurality of pixel parts and each pixel part includes two or more pixelsthat display different colors from each other. In the present exemplaryembodiment shown in FIG. 1, each pixel part includes a first pixel PX1,a second pixel PX2, and a third pixel PX3, which display a red color R,a green color G, and a blue color B, respectively. Although not shown inFIG. 1, the pixel parts are arranged in a matrix.

The liquid crystal display panel 400 includes a plurality of gate linesand a plurality of data lines. In FIG. 1, gate lines and data lines thatare related to the first, second, and third pixels PX1, PX2, and PX3 areshown. In detail, as shown in FIG. 1, the liquid crystal display panel400 includes first to fourth data lines DL1, DL2, DL3, and DL4 that aresubstantially parallel to each other and first and second gate lines GL1and GL2 that are insulated from the first to fourth data lines DL1 toDL4 while crossing the first to fourth data lines DL1 to DL4.

In addition, the liquid crystal display panel 400 further includes afirst storage line SL1, a second storage line SL2 substantially parallelto the first storage line SL1, first and second branch electrodes LSL1and RSL1 branched from the first storage line SL1, and third and fourthbranch electrodes LSL2 and RSL2 branched from the second storage lineSL2.

Each of the first, second, and third pixels PX1, PX2, and PX3 includes afirst sub-pixel and a second sub-pixel. Since the first, second, andthird pixels PX1, PX2, and PX3 have a similar structure and function,the first pixel PX1 will be described in detail as a representativepixel, and details of the second and third pixels PX2 and PX3 will beomitted to avoid redundancy.

In addition, FIG. 2 shows the equivalent circuit configurationcorresponding to the first pixel PX1, but each of the second and thirdpixels PX2 and PX3 has the same circuit configuration as the first pixelPX1.

Referring to FIGS. 1 and 2, the first pixel PX1 includes a firstsub-pixel SPX1 and a second sub-pixel SPX2. The first sub-pixel SPX1includes a first thin film transistor Tr1 and a first sub-pixelelectrode 131 a, and the second sub-pixel SPX2 includes a second thinfilm transistor Tr2, a second sub-pixel electrode 131 b, a third thinfilm transistor Tr3, and a coupling capacitor Ccp. The first and secondsub-pixels SPX1 and SPX2 are disposed between the first and second datalines DL1 and DL2 that are adjacent to each other.

The first thin film transistor Tr1 is connected to the first data lineDL1 and the first gate line GL1, and the second thin film transistor Tr2is connected to the first data line DL1 and the first gate line GL1. Indetail, the first thin film transistor Tr1 includes a first sourceelectrode SE1 connected to the first data line DL1, a first gateelectrode GE1 connected to the first gate line GL1, and a first drainelectrode DE1 connected to the first sub-pixel electrode 131 a. Thefirst sub-pixel electrode 131 a faces a common electrode (not shown)while interposing a liquid crystal layer (not shown) therebetween toform a first liquid crystal capacitor Clc1. In addition, the firstsub-pixel electrode 131 a overlaps with the first storage line SL1 andfirst and second branch electrodes LSL1 and RSL1 to form a first storagecapacitor Cst1. Accordingly, the first storage capacitor Cst1 may beconnected to the first liquid crystal capacitor Clc1 in parallel.

The second thin film transistor Tr2 includes a second source electrodeSE2 connected to the first data line DL1, a second gate electrode GE2connected to the first gate line GL1, and a second drain electrode DE2connected to the second sub-pixel electrode 131 b. The second sub-pixelelectrode 131 b faces the common electrode while interposing the liquidcrystal layer therebetween to form a second liquid crystal capacitorClc2. In addition, the second sub-pixel electrode 131 b overlaps withthe second storage line SL2, and the third and fourth branch electrodesLSL2 and RSL2 to form a second storage capacitor Cst2. Thus, the secondstorage capacitor Cst2 may be connected to the second liquid crystalcapacitor Clc2 in parallel.

When a first gate signal is applied to the first gate line GL1, thefirst and second thin film transistors Tr1 and Tr2 are substantiallysimultaneously turned on. The data voltage applied to the first dataline DL1 is applied to the first and second sub-pixel electrodes 131 aand 131 b through the turned-on first and second thin film transistorsTr1 and Tr2. Accordingly, during a high period of the first gate signal,the first and second liquid crystal capacitors Clc1 and Clc2 are chargedwith the same pixel voltage.

Further, the third thin film transistor Tr3 includes a third sourceelectrode SE3 connected to the second drain electrode DE2 of the secondthin film transistor Tr2, a third gate electrode GE3 connected to thesecond gate line GL2, and a third drain electrode DE3 connected to thecoupling capacitor Ccp. In the present exemplary embodiment, thecoupling capacitor Ccp may include a first electrode CE1 extending fromthe third drain electrode DE3 and a second electrode CE2 extending fromthe second branch electrode RSL1 to face the first electrode CE1 whileinterposing an insulating layer (not shown) between the first and secondelectrodes CE1 and CE2, but the present invention is not limitedthereto.

The second gate line GL2 receives a second gate signal that rises afterthe fall transition of the first gate signal. When the third thin filmtransistor Tr3 is turned on in response to the second gate signal, avoltage division occurs between the second liquid crystal capacitor Clc2and the coupling capacitor Ccp, thereby lowering the pixel voltagecharged in the second liquid crystal capacitor Clc2. The lowering inlevel of the pixel voltage may be varied depending upon the rate ofcharge of the coupling capacitor Ccp.

Consequently, after the second gate signal is generated, the firstliquid crystal capacitor Clc1 may be charged with a first pixel voltageand the second liquid crystal capacitor Clc2 may be charged with asecond pixel voltage lower than the first pixel voltage.

As shown in FIG. 1, the second pixel PX2 includes a first sub-pixelelectrode 132 a and a second sub-pixel electrode 132 b, and the thirdpixel PX3 includes a first sub-pixel electrode 133 a and a secondsub-pixel electrode 133 b.

In the present exemplary embodiment, a voltage ratio of the second pixelvoltage to the first pixel voltage in the third pixel PX3 may be thesame as a voltage ratio of the second pixel voltage to the first pixelvoltage in each of the first and second pixels PX1 and PX2.

In addition, an area ratio of the second sub-pixel electrode 133 b tothe first sub-pixel electrode 133 a in the third pixel PX3 may be thesame as an area ratio of the second sub-pixel electrode 131 b and 132 bto the first sub-pixel electrode 131 a and 132 a in each of the firstand second pixels PX1 and PX2.

Each of the first sub-pixel electrodes 131 a, 132 a, and 133 a isdivided into first to fourth domains DM1 to DM4 having liquid crystalalignment directions different from each other. In the present exemplaryembodiment, the liquid crystal alignment directions of the first tofourth domains DM1 to DM4 are in a counter-clockwise direction. Inaddition, each of the second sub-pixel electrodes 131 b, 132 b, and 133b is divided into first to fourth domains DM1 to DM4 having liquidcrystal alignment directions different from each other. In the presentexemplary embodiment, the liquid crystal alignment directions in thefirst to fourth domains DM1 to DM4 of the second sub-pixel electrodes131 b, 132 b, and 133 b are in the counter-clockwise direction.

The liquid crystal alignment directions of the first to fourth domainsDM1 to DM4 will be described in detail with reference to FIGS. 4A to 4Cand 5A to 5C.

Further, the first sub-pixel electrode of at least one pixel of thefirst to third pixels PX1, PX2, and PX3 of the pixel part is providedwith a plurality of slits 134 a, 134 b, 134 c, and 134 d. As an example,the slits 134 a, 134 b, 134 c, and 134 d may be provided to the firstsub-pixel electrode 133 a included in the third pixel PX3 that displaysthe blue color. The slits 134 a, 134 b, 134 c, and 134 d include first,second, third, and fourth slits 134 a, 134 b, 134 c, and 134 drespectively corresponding to the first, second, third, and fourthdomains DM1, DM2, DM3, and DM4, and each of the first to fourth slits134 a, 134 b, 134 c, and 134 d is formed substantially parallel to theliquid crystal alignment direction of the corresponding domain. Theslits may also be formed in other arrangements, for example,substantially perpendicular, with respect to the liquid crystalalignment direction of their corresponding domains.

In the case that the liquid crystal alignment directions of the first tofourth domains DM1 to DM4 are in the counter-clockwise direction, first,second, third and fourth fringe fields FF1, FF2, FF3, and FF4 are formedin the first sub-pixel electrode 133 a.

The first fringe field area FF1 is formed along an end of the firstdomain DM1 and has an L shape, and the second fringe field area FF2 isformed along an end of the second domain DM2 and has an L shape rotated90 degrees in the counter-clockwise direction with respect to theposition of the L shape in the first domain DM1. The fringe field areaFF3 is formed along an end of the third domain DM3 and has an L shaperotated 90 degrees in the clockwise direction with respect to theposition of the L shape in the first domain DM1. The fourth fringe areaFF4 is formed along an end of the fourth domain DM4 and has an L shaperotated 180 degrees in the counter-clockwise direction with respect tothe position of the L shape in the first domain DM1. In the presentexemplary embodiment, the first to fourth fringe field areas FF1 to FF4may be areas in which the liquid crystal molecules are misaligned due tothe liquid crystal alignment directions colliding.

The first slits 134 a are provided in the first fringe field area FF1.Particularly, the first slits 134 a are formed by cutting the firstsub-pixel electrode 133 a from a side of the first sub-pixel electrode133 a inward to the first domain DM1 such that the first slits 134 a areformed substantially parallel to the liquid crystal alignment directionof the first domain DM1. The second slits 134 b are provided in thesecond fringe field area FF2. Particularly, the second slits 134 b areformed by cutting the first sub-pixel electrode 133 a from a side of thefirst sub-pixel electrode 133 a inward to the second domain DM2 suchthat the second slits 134 b are formed substantially parallel to theliquid crystal alignment direction of the second domain DM2.

The third slits 134 c are provided in the third fringe field area FF3.Particularly, the third slits 134 c are formed by cutting the firstsub-pixel electrode 133 a from a side of the first sub-pixel electrode133 a inward to the third domain DM3 such that the third slits 134 c areformed substantially parallel to the liquid crystal alignment directionof the third domain DM3. The fourth slits 134 d are provided in thefourth fringe field area FF4. Particularly, the fourth slits 134 d areformed by cutting the first sub-pixel electrode 133 a from a side of thefirst sub-pixel electrode 133 a inward to the fourth domain DM4 suchthat the fourth slits 134 d are formed substantially parallel to theliquid crystal alignment direction of the fourth domain DM4.

In the present exemplary embodiment, each of the first to fourth slits134 a to 134 d may have a length corresponding to approximately 10percent of a width of the first sub-pixel electrode 133 a. In addition,the entire area in which the first to fourth slits 134 a to 134 d areformed corresponds to about 10 percent to about 90 percent of the entirearea of the first sub-pixel electrode 133 a.

FIG. 3 is a cross-sectional view taken along a line I-I′ of FIG. 1.

Referring to FIG. 3, the liquid crystal display panel 400 includes anarray substrate 100, an opposite substrate 200 facing the arraysubstrate 100, and a liquid crystal layer 300 disposed between the arraysubstrate 100 and the opposite substrate 200.

The array substrate 100 includes a first base substrate 110 that is atransparent insulating substrate. The first base substrate 110 includesa gate line part including the first and second gate lines GL1 and GL2,the first and second storage lines SL1 and SL2, and the first to fourthbranch electrodes LSL1, RSL1, LSL2, and RSL2.

The array substrate 100 includes a gate insulating layer 121 that coversthe gate line part, and a data line part including the first to fourthdata lines DL1 to DL4 is disposed on the gate insulating layer 121. Thedata line part is covered by a protective layer 122 and an organicinsulating layer 123 is disposed on the protective layer 122.

The first sub-pixel electrodes 131 a, 132 a, and 133 a and the secondsub-pixel electrodes 131 b, 132 b, and 133 b are disposed on the organicinsulating layer 123.

The array substrate 100 further includes a first alignment layer 140 tocover the first sub-pixel electrodes 131 a, 132 a, and 133 a and thesecond sub-pixel electrodes 131 b, 132 b, and 133 b. The first alignmentlayer 140 may include a polymer material in which decomposition,dimerization, or isomerization occurs when irradiated by light such asan ultraviolet ray or a laser. In addition, the first alignment layer140 may be formed by blending an oligomer cinnamate and a polymer-basedcinnamate.

The opposite substrate 200 includes a second base substrate 210 facingthe first base substrate 110. The second base substrate 210 includes acolor filter layer 220 including red, green, and blue color pixels R, G,and B thereon. The red, green, and blue color pixels R, G, and Bcorrespond to the first, second, and third pixels PX1, PX2, and PX3,respectively.

The common electrode 230 is disposed on the color filter layer 220. Thecommon electrode 230 faces the first sub-pixel electrodes 131 a, 132 a,and 133 a to form the first liquid crystal capacitor Clc1. Although notshown in FIGS. 1 and 2, the common electrode 230 faces the secondsub-pixel electrodes 131 b, 132 b, and 133 b to form the second liquidcrystal capacitor Clc2.

The opposite substrate 200 further includes a second alignment layer 240to cover the common electrode 230. The second alignment layer 240 mayinclude a polymer material in which decomposition, dimerization, orisomerization occurs when irradiated by light such as an ultraviolet rayor laser. In addition, the second alignment layer 240 may be formed byblending an oligomer cinnamate and a polymer-based cinnamate.

FIG. 4A is a plan view showing alignment directions of a first alignmentlayer according to an exemplary embodiment of the present invention,FIG. 4B is a plan view showing alignment directions of a secondalignment layer according to an exemplary embodiment of the presentinvention, and FIG. 4C is a plan view showing a first sub-pixel and asecond sub-pixel according to an exemplary embodiment of the presentinvention.

Referring to FIG. 4A, the first alignment layer 140 is divided into afirst sub-pixel area SPA1 and a second sub-pixel area SPA2 to correspondto the third pixel PX3. In addition, each of the first and secondsub-pixel areas SPA1 and SPA2 includes a first area A1 and a second areaA2 arranged in a direction vertical to a first direction D1. The firstarea A1 is light-aligned in the first direction D1 and the second areaA2 is light-aligned in a second direction D2 opposite to the firstdirection D1. The first alignment layer 140 may be further divided intoadditional sub-pixel areas which may be light-aligned in the first orsecond directions or some other direction, thus generating more domains.

The alignment direction of the first alignment layer 140 may bedetermined by irradiating an ultraviolet ray having two or morepolarizing directions onto the first alignment layer 140 or byinclinedly irradiating light onto the first alignment layer 140 withrespect to a surface of the first alignment layer 140.

Hereinafter, the method of inclinedly irradiating the light onto thefirst alignment layer 140 will be described.

A mask through which an opening is formed is disposed on the firstalignment layer 140. When the mask is disposed such that the openingcorresponds to the first area A1, the light is inclinedly irradiatedonto the first area A1 of the first alignment layer 140 to perform afirst exposure process on the first area A1 of the first alignment layer140. During the first exposure process, an exposure apparatus (notshown) emitting the light may irradiate the light onto the first area A1while being moved in the first direction D1.

The method of inclinedly irradiating the light onto the first alignmentlayer 140 may be performed by inclining the first base substrate 110 orthe exposure apparatus.

Then, after the mask is shifted such that the opening corresponds to thesecond area A2, the light is inclinedly irradiated onto the second areaA2 of the first alignment layer 140 to perform a second exposure processon the second area A2 of the first alignment layer 140. Particularly,during the second exposure process, the exposure apparatus irradiatesthe light onto the second area A2 while being moved in the seconddirection D2 opposite to the first direction D1. When the exposureprocesses are completely finished, a pretilt angle is formed to beinclined toward the first direction D1 in the first area A1 of the firstalignment layer 140, and a pretilt angle is formed to be inclined towardthe second direction D2 in the second area A2 of the first alignmentlayer 140. For instance, the pretilt angle may be in a range of about 85degrees to about 89 degrees. Accordingly, the liquid crystal moleculesof the liquid crystal layer 300 may be vertically aligned by the firstalignment layer 140 while being inclined by the pretilt angle when noelectric field is applied. In the present exemplary embodiment, the sizeof the pretilt angle depends upon the amount of the irradiated light. Inother words, as the amount of irradiated light increases, the size ofthe pretilt angle increases, and vice versa.

In the present exemplary embodiment, the first alignment layer 140 hasbeen aligned by using a light alignment method capable of accuratelycontrolling the liquid crystal alignment direction, but the presentinvention is not limited thereto. In other words, the first alignmentlayer 140 may be aligned by various alignment methods such as a rubbingmethod or an alignment method which uses a reactive mesogen.

Referring to FIG. 4B, the second alignment layer 240 is divided into afirst sub-pixel area SPA1 and a second sub-pixel area SPA2 to correspondto the third pixel PX3. In addition, each of the first and secondsub-pixel areas SPA1 and SPA2 includes a third area A3 and a fourth areaA4 arranged in the first direction D1. The third area A3 islight-aligned in a third direction D3 vertical to the first direction D1and the fourth area A4 is light-aligned in a fourth direction D4opposite to the third direction D3. The second alignment layer 240 maybe further divided into additional sub-pixel areas which may belight-aligned in the third or fourth directions or some other direction,thus generating more domains.

Since the second alignment layer 240 is aligned by a method similar tothat of the first alignment layer 140, a detailed description thereofwill be omitted.

When the array substrate 100 and the opposite substrate 200 are coupledwith each other to face each other, as shown in FIG. 4C, the first tofourth domains DM1 to DM4 are formed in the first sub-pixel area SPA1.In detail, the first area A1 overlaps the third area A3 to form thefirst domain DM1, the first area A1 overlaps the fourth area A4 to formthe second domain DM2, the second area A2 overlaps the third area A3 toform the third domain DM3, and the second area A2 overlaps the fourtharea A4 to form the fourth domain DM4.

Similar to the above, the first to fourth domains DM1 to DM4 are formedin the second sub-pixel area SPA2.

The liquid crystal molecules in the liquid crystal layer 300 are alignedin different directions from each other in the first to fourth domainsDM1 to DM4. In particular, the liquid crystal molecules in the firstdomain DM1 are aligned in a fifth direction D5 determined by a vectorsum of the second direction D2 and the third direction D3, the liquidcrystal molecules in the second domain DM2 are aligned in a sixthdirection D6 determined by a vector sum of the second direction D2 andthe fourth direction D4, the liquid crystal molecules in the thirddomain DM3 are aligned in a seventh direction D7 determined by a vectorsum of the first direction D1 and the third direction D3, and the liquidcrystal molecules in the fourth domain DM4 are aligned in an eighthdirection D8 determined by a vector sum of the first direction D1 andthe fourth direction D4.

Accordingly, the alignment directions of the liquid crystal layer 300are in the counter-clockwise direction in the first to fourth domainsDM1 to DM4. As described above, plural domains DM1 to DM4, e.g., thefirst to fourth domains, may be formed in each sub-pixel area SPA1 andSPA2, e.g., the first and second sub-pixel areas, thereby widening aviewing angle of the liquid crystal display panel 400.

Further, the first to fourth slits 134 a, 134 b, 134 c, and 134 d areformed corresponding to the first to fourth domains DM1 to DM4,respectively. Especially, the first slits 134 a are alignedsubstantially parallel to the fifth direction D5 in the first domainDM1, and the second slits 134 b are aligned substantially parallel tothe sixth direction D6 in the second domain DM2. The third slits 134 care aligned substantially parallel to the seventh direction D7 in thethird domain DM3, and the fourth slits 134 d are aligned substantiallyparallel to the eighth direction D8 in the fourth domain DM4.

FIG. 5A is a plan view showing alignment directions of a first alignmentlayer according to an exemplary embodiment of the present invention,FIG. 5B is a plan view showing alignment directions of a secondalignment layer according to an exemplary embodiment of the presentinvention, and FIG. 5C is a plan view showing a first sub-pixel and asecond sub-pixel according to an exemplary embodiment of the presentinvention.

Referring to FIG. 5A, the first alignment layer 140 is divided into thefirst sub-pixel area SPA1 and the second sub-pixel area SPA2 tocorrespond to the third pixel PX3. In addition, each of the first andsecond sub-pixel areas SPA1 and SPA2 includes the first area A1 and thesecond area A2 arranged in a direction vertical to the first directionD1. The first area A1 is light-aligned in the first direction D1 and thesecond area A2 is light-aligned in the second direction D2 opposite tothe first direction D1.

The light is inclinedly irradiated onto the first area A1 of the firstalignment layer 140 to perform the first exposure process on the firstarea A1 of the first alignment layer 140. Then, the light is inclinedlyirradiated onto the second area A2 of the first alignment layer 140 toperform the second exposure process on the second area A2 of the firstalignment layer 140. When the exposure processes are completelyfinished, the pretilt angle is formed to be inclined toward the firstdirection D1 in the first area A1 of the first alignment layer 140, andthe pretilt angle is formed to be inclined toward the second directionD2 in the second area A2 of the first alignment layer 140. Accordingly,the liquid crystal molecules of the liquid crystal layer 300 may bevertically aligned by the first alignment layer 140 while being inclinedby the pretilt angle when no electric field is applied.

Referring to FIG. 5B, the second alignment layer 240 is divided into thefirst sub-pixel area SPA1 and the second sub-pixel area SPA2 tocorrespond to the third pixel PX3. In addition, each of the first andsecond sub-pixel areas SPA1 and SPA2 includes the third area A3 and thefourth area A4 arranged in the first direction D1. The third area A3 islight-aligned in the third direction D3 vertical to the first directionD1 and the fourth area A4 is light-aligned in the fourth direction D4opposite to the third direction D3.

When the array substrate 100 and the opposite substrate 200 are coupledwith each other to face each other, as shown in FIG. 5C, the first tofourth domains DM1 to DM4 are formed in the first sub-pixel area SPA1.In detail, the first area A1 overlaps the third area A3 to form thefirst domain DM1, the first area A1 overlaps the fourth area A4 to formthe second domain DM2, the second area A2 overlaps the third area A3 toform the third domain DM3, and the second area A2 overlaps the fourtharea A4 to form the fourth domain DM4.

Similar to the above, the first to fourth domains DM1 to DM4 are formedin the second sub-pixel area SPA2.

The liquid crystal molecules in the liquid crystal layer 300 are alignedin different directions from each other in the first to fourth domainsDM1 to DM4. Particularly, the liquid crystal molecules in the firstdomain DM1 are aligned in a fifth direction D5 determined by a vectorsum of the second direction D2 and the third direction D3, the liquidcrystal molecules in the second domain DM2 are aligned in a sixthdirection D6 determined by a vector sum of the second direction D2 andthe fourth direction D4, the liquid crystal molecules in the thirddomain DM3 are aligned in a seventh direction D7 determined by a vectorsum of the first direction D1 and the third direction D3, and the liquidcrystal molecules in the fourth domain DM4 are aligned in an eighthdirection D8 determined by a vector sum of the first direction D1 andthe fourth direction D4.

Accordingly, the alignment direction of the liquid crystal layer in thesecond domain DM2 is opposite to the alignment direction of the liquidcrystal layer in the third domain DM3, and the alignment direction ofthe liquid crystal layer in the first domain DM1 is opposite to thealignment direction of the liquid crystal layer in the fourth domainDM4. As described above, plural domains DM1 to DM4 having differentalignment directions may be formed in each sub-pixel area SPA1 and SPA2,to thereby widen the viewing angle of the liquid crystal display panel400.

Further, the first to fourth slits 134 a, 134 b, 134 c, and 134 d areformed corresponding to the first to fourth domains DM1 to DM4,respectively. Especially, the first slits 134 a are alignedsubstantially parallel to the fifth direction D5 in the first domainDM1, and the second slits 134 b are aligned substantially parallel tothe sixth direction D6 in the second domain DM2. The third slits 134 care aligned substantially parallel to the seventh direction D7 in thethird domain DM3, and the slits 134 d are aligned substantially parallelto the eighth direction D8 in the fourth domain DM4.

The first to fourth domains DM1 to DM4 may have different liquid crystalalignment directions than those shown in FIGS. 4C and 5C.

FIG. 6 is a graph showing side gamma curves of two liquid crystaldisplay panels. In FIG. 6, a first graph G1 represents the side gammacurve according to a comparison example in which no slits 134 a, 134 b,134 c, and 134 d are formed in the first sub-pixel electrode 133 a, anda second graph G2 represents the side gamma curve according to anexemplary embodiment of the present invention in which the slits 134 a,134 b, 134 c, and 134 d are formed in the first sub-pixel electrode 133a.

Referring to FIG. 6, the gamma curve is shifted to the left when theslits 134 a, 134 b, 134 c, and 134 d are formed in the first sub-pixelelectrode 133 a versus when the slits 134 a, 134 b, 134 c, and 134 d arenot formed in the first sub-pixel electrode 133 a.

Consequently, when the slits 134 a, 134 b, 134 c, and 134 d are formedin the first sub-pixel electrode 133 a, output gray scales with respectto input gray scales are higher, after a specific input gray scale value(e.g., around input gray scale 100), in comparison with when the slits134 a, 134 b, 134 c, and 134 d are not formed in the first sub-pixelelectrode 133 a.

FIG. 7 is a graph showing side gamma curves of first, second, and thirdpixels displaying red, green, and blue colors, respectively. In FIG. 7,a third graph G3 represents the side gamma curve of the first pixel PX1,a fourth graph G4 represents the side gamma curve of the second pixelPX2, and a fifth graph G5 represents the side gamma curve of the thirdpixel PX3.

Referring to FIG. 7, after the specific input gray scale value (e.g.,input gray scale 100), the output gray scale of the third pixel PX3 islow compared with the output gray scale of the first and second pixelsPX1 and PX2 with respect to the same input gray scale values.Consequently, when the blue gamma value (of the third pixel PX3) isdifferent from the red and green gamma values (of the first and secondpixels PX1 and PX2, respectively) in a specific input gray scale range(e.g., around input gray scale 128), a white color coordinate (Wx, Wy)moves to a yellow wavelength range, thereby causing deterioration invisibility.

However, when the slits 134 a, 134 b, 134 c, and 134 d are formed in thefirst sub-pixel electrode 133 a of the third pixel PX3 as shown in FIG.1, the blue gamma curve moves to the left. Consequently, when the slits134 a, 134 b, 134 c, and 134 d are formed in the first sub-pixelelectrode 133 a of the third pixel PX3, the white color coordinate (Wx,Wy) may be prevented from moving to the yellow wavelength range.

FIG. 8 is a graph showing x-coordinate values and y-coordinate values oftwo white color coordinate values. In FIG. 8, sixth and seventh graphsG6 and G7 represent an x-coordinate value Wx and a y-coordinate valueWy, respectively, according to a comparison example in which the slits134 a, 134 b, 134 c, and 134 d are not formed in the first sub-pixelelectrode 133 a, and eighth and ninth graphs G8 and G9 represent anx-coordinate value Wx and a y-coordinate value Wy, respectively,according to an exemplary embodiment of the present invention in whichthe slits 134 a, 134 b, 134 c, and 134 d are formed in the firstsub-pixel electrode 133 a.

Referring to FIG. 8, in the case that the slits 134 a, 134 b, 134 c, and134 d are not formed in the first sub-pixel electrode 133 a, the whitecolor coordinate value (Wx, Wy) is increased in the specific input grayscale range (e.g., around input gray scale 128).

However, when the slits 134 a, 134 b, 134 c, and 134 d are formed in thefirst sub-pixel electrode 133 a, the white color coordinate value (Wx,Wy) is uniform over the whole gray scale range. In other words, when theslits 134 a, 134 b, 134 c, and 134 d are formed in the first sub-pixelelectrode 133 a, the white color coordinate value (Wx, Wy) may beprevented from moving to the yellow wavelength range in the specificinput gray scale range (e.g., around input gray scale 128).

FIG. 9 is a graph showing a variation of side gamma curves according toa voltage ratio of the second sub-pixel electrode to the first sub-pixelelectrode, according to an exemplary embodiment of the presentinvention. In FIG. 9, a tenth graph G10 represents that the voltageratio of the second pixel voltage charged in the second sub-pixel to thefirst pixel voltage charged in the first sub-pixel is about 0.75, aneleventh graph G11 represents that the voltage ratio of the second pixelvoltage to the first pixel voltage is about 0.8, and a twelfth graph G12represents that the voltage ratio of the second pixel voltage to thefirst pixel voltage is about 0.85.

Referring to FIG. 9, as the voltage ratio of the second pixel voltage tothe first pixel voltage becomes large, the side gamma curve moves to theleft. Consequently, the side gamma curve of the blue pixel, e.g., thethird pixel PX3, moves to the left as the voltage difference between thefirst pixel voltage and the second pixel voltage becomes large.

As shown in FIG. 7, to compensate for the blue gamma value that isdifferent from the red and green gamma values with respect to the sameinput gray scale, the voltage ratio of the second pixel voltage to thefirst pixel voltage in the third pixel PX3 may be set to be differentfrom the voltage ratio of the second pixel voltage to the first pixelvoltage in each of the first and second pixels PX1 and PX2.

In detail, the voltage ratio of the second pixel voltage to the firstpixel voltage in the third pixel PX3 is larger than the voltage ratio ofthe second pixel voltage to the first pixel voltage in each of the firstand second pixels PX1 and PX2. In addition, the voltage ratio of thesecond pixel voltage to the first pixel voltage in the first pixel PX1is equal to or smaller than the voltage ratio of the second pixelvoltage to the first pixel voltage in the second pixel PX2.

As an example, the voltage ratio of the second pixel voltage to thefirst pixel voltage in the first pixel PX1 is set to about 0.59 to about0.845, and the voltage ratio of the second pixel voltage to the firstpixel voltage in the second pixel PX2 is set to about 0.6 to about 0.85.In this case, the voltage ratio of the second pixel voltage to the firstpixel voltage in the third pixel PX3 is set to about 0.61 to about 0.9.

As described above, when the voltage ratio of the second pixel voltageto the first pixel voltage in the third pixel PX3 is set to be largerthan the voltage ratio of the second pixel voltage to the first pixelvoltage in each of the first and second pixels PX1 and PX2, thedifference between the blue gamma value and the red gamma value andbetween the blue gamma value and the green gamma value may be reduced.

FIG. 10 is a graph showing a variation of gamma curves according to anarea ratio of the second sub-pixel electrode to the first sub-pixelelectrode, according to an exemplary embodiment of the presentinvention. In FIG. 10, a thirteenth graph G13 represents that the arearatio of the second sub-pixel electrode to the first sub-pixel electrodeis 1:1.6, a fourteenth graph G14 represents that the area ratio of thesecond sub-pixel electrode to the first sub-pixel electrode is 1:2, anda fifteenth graph G15 represents that the area ratio of the secondsub-pixel electrode to the first sub-pixel electrode is 1:2.4.

Referring to FIG. 10, as the area ratio of the second sub-pixelelectrode 133 b to the first sub-pixel electrode 133 a becomes large,the gamma curve moves to the left. Consequently, the blue gamma curvemoves to the left as the second sub-pixel electrode 133 b becomes largerthan the first sub-pixel electrode 133 a.

As shown in FIG. 7, to compensate for the blue gamma value that isdifferent from the red and green gamma values with respect to the sameinput gray scale, the area ratio of the second sub-pixel electrode 133 bto the first sub-pixel electrode 133 a in the third pixel PX3 may be setto be different from the area ratio of the second sub-pixel electrodes131 b and 132 b to the first sub-pixel electrodes 131 a and 132 a in thefirst and second pixels PX1 and PX2.

In detail, the area ratio of the second sub-pixel electrode 133 b to thefirst sub-pixel electrode 133 a in the third pixel PX3 is larger thanthe area ratio of the second sub-pixel electrode 132 b to the firstsub-pixel electrode 132 a in the second pixel PX2. As an example, thearea ratio of the second sub-pixel electrode 133 b to the firstsub-pixel electrode 133 a in the third pixel PX3 is about 1:1.1 to about1:3.5, and the area ratio of the second sub-pixel electrode 132 b to thefirst sub-pixel electrode 132 a in the second pixel PX2 is about 1:1 toabout 1:2.5. In this case, the area ratio of the second sub-pixelelectrode 132 b to the first sub-pixel electrode 132 a in the secondpixel PX2 is equal to the area ratio of the second sub-pixel electrode131 b to the first sub-pixel electrode 131 a in the first pixel PX1.

As described above, when the area ratio of the second sub-pixelelectrode 133 b to the first sub-pixel electrode 133 a in the thirdpixel PX3 is set to be larger than the area ratio of the secondsub-pixel electrodes 131 b and 132 b to the first sub-pixel electrodes131 a and 132 a in the first and second pixels PX1 and PX2, thedifference between the blue gamma value and the red gamma value andbetween the blue gamma value and the green gamma value may be reduced.

FIG. 11 is a plan view showing a pixel part of a liquid crystal displaypanel 405 according to an exemplary embodiment of the present invention.In FIG. 11, the same reference numerals denote the same elements in FIG.1, and thus detailed descriptions of the same elements will be omitted.

Referring to FIG. 11, each of the first sub-pixel electrodes 131 a, 132a, and 133 a is divided into the first to fourth domains DM1 to DM4having the different liquid crystal alignment directions from eachother. As an example, the liquid crystal alignment directions of thefirst to fourth domains DM1 to DM4 are in the counter-clockwisedirection. In addition, each of the second sub-pixel electrodes 131 b,132 b, and 133 b is divided into the first to fourth domains DM1 to DM4having the different liquid crystal alignment directions from eachother. As an example, the liquid crystal alignment directions of thefirst to fourth domains DM1 to DM4 are in the counter-clockwisedirection.

The first and second sub-pixel electrodes of one or more of the first,second, and third pixels PX1, PX2, and PX3 for the pixel part areprovided with a plurality of slits. In the present exemplary embodiment,the first sub-pixel electrode 133 a included in the third pixel PX3 thatdisplays the blue color among the first, second, and third pixels PX1,PX2, and PX3 may be provided with the slits.

The slits include fifth, sixth, seventh, and eighth slits 135 a, 135 b,135 c, and 135 d respectively corresponding to the first, second, third,and fourth domains DM1 to DM4, and each of the fifth to eighth slits 135a, 135 b, 135 c, and 135 d is formed substantially parallel to theliquid crystal alignment direction of the corresponding domain among thefirst to fourth domains DM1 to DM4. As an example, the fifth to eighthslits 135 a, 135 b, 135 c, and 135 d are formed in the first sub-pixelelectrode 133 a except for an area in which the fringe field is formed.

In detail, the fifth slit 135 a is formed by cutting the first sub-pixelelectrode 133 a from a first side of the first sub-pixel electrode 133 aamong four sides of the first sub-pixel electrode 133 a, which issubstantially parallel to and disposed on the first storage line SL1,inward to the first domain DM1 such that the fifth slit 135 a is formedsubstantially parallel to the liquid crystal alignment direction of thefirst domain DM1. The sixth slit 135 b is formed by cutting the firstsub-pixel electrode 133 a from a second side of the first sub-pixelelectrode 133 a among four sides of the first sub-pixel electrode 133 a,which is substantially parallel to and disposed on the first branchelectrode LSL1, inward to the second domain DM2 such that the sixth slit135 b is formed substantially parallel to the liquid crystal alignmentdirection of the second domain DM2.

The seventh slit 135 c is formed by cutting the first sub-pixelelectrode 133 a from a third side of the first sub-pixel electrode 133 aamong four sides of the first sub-pixel electrode 133 a, which issubstantially parallel to the first storage line SL1 and disposedadjacent to the first gate line GL1, inward to the third domain DM3 suchthat the seventh slit 135 c is formed substantially parallel to theliquid crystal alignment direction of the third domain DM3. The eighthslit 135 d is formed by cutting the first sub-pixel electrode 133 a froma fourth side of the first sub-pixel electrode 133 a among four sides ofthe first sub-pixel electrode 133 a, which is substantially parallel toand disposed on the second branch electrode RSL1, inward to the fourthdomain DM4 such that the eighth slit 135 d is formed substantiallyparallel to the liquid crystal alignment direction of the fourth domainDM4.

In the present exemplary embodiment, each of the fifth to eighth slits135 a to 135 d may have a length corresponding to approximately 10percent of a width of the first sub-pixel electrode 133 a. In addition,the entire area in which the first to fourth slits 134 a to 134 d areformed corresponds to about 10 percent to about 90 percent of the entirearea of the first sub-pixel electrode 133 a.

FIG. 12A is a plan view showing a first sub-pixel electrode of a thirdpixel according to an exemplary embodiment of the present invention, andFIG. 12B is a plan view showing a first sub-pixel electrode of a thirdpixel according to an exemplary embodiment of the present invention.

Referring to FIG. 12A, the first sub-pixel electrode 133 a includes thefirst to fourth domains DM1 to DM4 having different liquid crystalalignment directions from each other.

The alignment directions of the liquid crystal layer 300 in the first tofourth domains DM1 to DM4 are in the counter-clockwise direction. Inthis case, a fringe field area FFT corresponding to boundaries betweenthe first to fourth domains DM1 to DM4 is formed in the first sub-pixelelectrode 133 a.

In addition, the first sub-pixel electrode 133 a includes an effectivedisplay area AA in which the image is substantially displayed and anon-display area NA surrounding the effective display area AA.

Further, the fifth to eighth slits 135 a, 135 b, 135 c, and 135 d areformed to respectively correspond to the first to fourth domains DM1 toDM4 and positioned in the area in which the fringe field area FFT is notpositioned. In addition, the fifth to eighth slits 135 a, 135 b, 135 c,and 135 d may be formed in the non-display area NA. Accordingly, thetransmittance of the third pixel PX3 may be prevented from being lowereddue to the fifth to eighth slits 135 a, 135 b, 135 c, and 135 d.

As shown in FIG. 12B, the fifth to eighth slits 135 a, 135 b, 135 c, and135 d may be extended to the effective area AA.

FIG. 13 is a graph showing a liquid crystal response characteristic of afirst pixel and a third pixel, according to an exemplary embodiment ofthe present invention. In FIG. 13, a sixteenth graph G16 represents theliquid crystal response characteristic of the first pixel PX1 and aseventeenth graph G17 represents the liquid crystal responsecharacteristic of the third pixel PX3.

Referring to FIG. 13, the initial response speed of the third pixel PX3in which the slits 135 a, 135 b, 135 c, and 135 d are formed is fasterthan the initial response speed of the first pixel PX1 in which theslits 135 a, 135 b, 135 c, and 135 d are not formed.

In FIGS. 11, 12A, and 12B, the structure in which the slits 135 a, 135b, 135 c, and 135 d are formed in the first sub-pixel electrode 133 a ofthe third pixel PX3 has been shown, but the slits 135 a, 135 b, 135 c,and 135 d may be formed in the first sub-pixel electrode 133 a of eachof the first and second pixels PX1 and PX2 to improve the response speedof each of these pixels.

FIG. 14 is an equivalent circuit diagram showing a pixel in a liquidcrystal display panel according to an exemplary embodiment of thepresent invention, and FIG. 15 is a plan view showing an array substrate410 including the pixel shown in FIG. 14, according to an exemplaryembodiment of the present invention.

Referring to FIGS. 14 and 15, a pixel PX according to an exemplaryembodiment of the present invention includes a first sub-pixel SPX1 anda second sub-pixel SPX2. The first sub-pixel SPX1 includes a first thinfilm transistor Tr1, a first liquid crystal capacitor Clc1, and a firststorage capacitor Cst1, and the second sub-pixel SPX2 includes a secondthin film transistor Tr2, a second liquid crystal capacitor Clc2, asecond storage capacitor Cst2, a third thin film transistor Tr3, and acoupling capacitor Ccp.

The first thin film transistor Tr1 includes a gate electrode GE1branched from the first gate line GL1, a source electrode SE1 branchedfrom the first data line DL1, and a first drain electrode DE1electrically connected to a first sub-pixel electrode 133 a. The firstsub-pixel electrode 133 a partially overlaps the first storage line SL1,the first branch electrode LSL1, and the second branch electrode RSL1 toform the first storage capacitor Cst1 as shown in FIG. 14.

The first sub-pixel electrode 133 a is divided into the first to fourthdomains DM1 to DM4 having the different liquid crystal alignmentdirections from each other. Especially, the liquid crystal alignmentdirections of the first to fourth domains DM1 to DM4 are in thecounter-clockwise direction. Fifth to eighth slits 135 a, 135 b, 135 c,and 135 d are formed in the first to fourth domains DM1 to DM4,respectively. Each of the fifth to eighth slits 135 a, 135 b, 135 c, and135 d is formed substantially parallel to the liquid crystal alignmentdirection of the corresponding domain among the first to fourth domainsDM1 to DM4.

The first sub-pixel electrode 133 a may include the first to fourthslits 134 a, 134 b, 134 c, and 134 d shown in FIG. 1.

Further, the second thin film transistor Tr2 includes a second gateelectrode GE2 branched from the first gate line GL1, a second sourceelectrode SE2 branched from the first data line DL1, and a second drainelectrode DE2 electrically connected to a second sub-pixel electrode 133b. The second sub-pixel electrode 133 b is divided into first to fourthdomains DM1 to DM4 having the different liquid crystal alignmentdirections from each other. Especially, the liquid crystal alignmentdirections of the first to fourth domains DM1 to DM4 are in thecounter-clockwise direction.

The third thin film transistor Tr3 includes a third gate electrode GE3branched from the first storage line SL1, a third source electrode SE3extended from the second drain electrode DE2, and a third drainelectrode DE3 connected to the coupling capacitor Ccp. The couplingcapacitor Ccp includes a first electrode CE1 extended from the thirddrain electrode DE3 and a second electrode CE2 extended from the firststorage line SL1 to face the first electrode CE1, but is not limitedthereto.

When a first gate signal is applied to the first gate line GL1, thefirst and second thin film transistors Tr1 and Tr2 are substantiallysimultaneously turned on. The data voltage applied to the first dataline DL1 is applied to the first and second liquid crystal capacitorClc1 and Clc2 through the turned-on first and second thin filmtransistors Tr1 and Tr2. Thus, the first and second liquid crystalcapacitors Clc1 and Clc2 may be charged with the same pixel voltage.

The third thin film transistor Tr3 is turned on in response to thestorage voltage applied to the first storage line SL1. When the thirdthin film transistor Tr3 is turned on by the storage voltage, a voltagedivision occurs between the first liquid crystal capacitor Clc1 and thecoupling capacitor Ccp according to the charge rate of the first liquidcrystal capacitor Clc1 and the charge rate of the coupling capacitorCcp. Consequently, while the first liquid crystal capacitor Clc1 ischarged with a first pixel voltage, the second liquid crystal capacitorClc2 is charged with a second pixel voltage smaller than the first pixelvoltage by the third thin film transistor Tr3 and the coupling capacitorCcp.

FIG. 16 is an equivalent circuit diagram showing a pixel in a liquidcrystal display panel according to an exemplary embodiment of thepresent invention, and FIG. 17 is a plan view showing an array substrate420 including the pixel shown in FIG. 16, according to an exemplaryembodiment of the present invention. In FIGS. 16 and 17, a pixel has astructure similar to that of FIG. 11 except for a second couplingcapacitor Ccp2.

Referring to FIGS. 16 and 17, a first coupling capacitor Ccp1 isprovided between the third drain electrode DE3 of the third thin filmtransistor Tr3 and the first storage line SL1. Particularly, the firstcoupling capacitor Ccp1 includes a first electrode CE1 extended from thethird drain electrode DE3 and a second electrode CE2 extended from thefirst storage line SL1 to face the first electrode CE1.

Further, the second coupling capacitor Ccp2 is provided between thethird drain electrode DE3 of the third thin film transistor Tr3 and thefirst sub-pixel electrode 133 a. In detail, the second couplingcapacitor Ccp2 includes a third electrode CE3 extended from the firstelectrode CE1 and a fourth electrode CE4 extended from the firstsub-pixel electrode 133 a to face the third electrode CE3.

The first sub-pixel electrode 133 a is divided into first to fourthdomains DM1 to DM4 having different liquid crystal alignment directionsfrom each other. The liquid crystal alignment directions of the first tofourth domains DM1 to DM4 are in the counter-clockwise direction. Thefifth to eighth slits 135 a, 135 b, 135 c, and 135 d are formed in thefirst to fourth domains DM1 to DM4, respectively. Each of the fifth toeighth slits 135 a, 135 b, 135 c, and 135 d is formed substantiallyparallel to the liquid crystal alignment direction of the correspondingdomain among the first to fourth domains DM1 to DM4.

The first sub-pixel electrode 133 a may include the first to fourthslits 134 a, 134 b, 134 c, and 134 d shown in FIG. 1.

Further, the second gate electrode GE2 of the second thin filmtransistor Tr2 is branched from the first gate line GL1 and the secondsource electrode SE2 is branched from the first data line DL1. Thesecond drain electrode DE2 of the second thin film transistor Tr2 iselectrically connected to the second sub-pixel electrode 133 b. Thesecond sub-pixel electrode 133 b is divided into first to fourth domainsDM1 to DM4 having different liquid crystal alignment directions fromeach other. The liquid crystal alignment directions of the first tofourth domains DM1 to DM4 are in the counter-clockwise direction.

When the third thin film transistor Tr3 is turned on in response to asecond gate signal applied to the second gate line GL2, a voltagedivision occurs between the first coupling capacitor Ccp1 and the secondcoupling capacitor Ccp2. Due to the voltage division, the first couplingcapacitor Ccp1 and the second liquid crystal capacitor Clc2 are chargedwith the same voltage, but the second pixel voltage charged in thesecond liquid crystal capacitor Clc2 becomes lower than the first pixelvoltage charged in the first liquid crystal capacitor Clc1.

In addition, when the first liquid crystal capacitor Clc1 is connectedto the first coupling capacitor Ccp1 through the second couplingcapacitor Ccp2, the first pixel voltage charged in the first liquidcrystal capacitor Clc1 may be increased by the coupling of the firstcoupling capacitor Ccp1.

FIG. 18 is an equivalent circuit diagram showing a pixel in a liquidcrystal display panel according to an exemplary embodiment of thepresent invention, and FIG. 19 is a plan view showing an array substrate430 including the pixel shown in FIG. 18, according to an exemplaryembodiment of the present invention.

Referring to FIGS. 18 and 19, a pixel PX includes a first sub-pixel SPX1and a second sub-pixel SPX2. The first sub-pixel SPX1 includes a thinfilm transistor Tr1, a first liquid crystal capacitor Clc1, and a firststorage capacitor Cst1, and the second sub-pixel SPX2 includes a secondthin film transistor Tr2, a second liquid crystal capacitor Clc2, and asecond storage capacitor Cst2.

The first thin film transistor Tr1 includes a first gate electrode GE1branched from the first gate line GL1, a first source electrode SE1branched from the first data line DL1, and a first drain electrode DE1electrically connected to the first sub-pixel electrode 133 a. The firstsub-pixel electrode 133 a partially overlaps the first storage line SL1,the first branch electrode LSL1, and the second branch electrode RSL1 toform the first storage capacitor Cst1.

The first sub-pixel electrode 133 a is divided into first to fourthdomains DM1 to DM4 having different liquid crystal alignment directionsfrom each other. The liquid crystal alignment directions of the first tofourth domains DM1 to DM4 are in the counter-clockwise direction. Thefifth to eighth slits 135 a, 135 b, 135 c, and 135 d are formed in thefirst to fourth domains DM1 to DM4, respectively. Each of the fifth toeighth slits 135 a, 135 b, 135 c, and 135 d is formed substantiallyparallel to the liquid crystal alignment direction of the correspondingdomain among the first to fourth domains DM1 to DM4.

The first sub-pixel electrode 133 a may include the first to fourthslits 134 a, 134 b, 134 c, and 134 d shown in FIG. 1.

The second thin film transistor Tr2 includes a second gate electrode GE2branched from the first gate line GL1, a second source electrode SE2branched from the second data line DL2, and a second drain electrode DE2electrically connected to the second sub-pixel electrode 133 b.

The second sub-pixel electrode 133 b partially overlaps the secondstorage line SL2, the third branch electrode LSL2, and the fourth branchelectrode RSL2 to form the second storage capacitor Cst2. The secondsub-pixel electrode 133 b is divided into first to fourth domains DM1 toDM4 having different liquid crystal alignment directions from eachother. The liquid crystal alignment directions of the first to fourthdomains DM1 to DM4 are in the counter-clockwise direction.

When the gate signal is applied to the first gate line GL1, the firstand second thin film transistors Tr1 and Tr2 are substantiallysimultaneously turned on. The first data voltage applied to the firstdata line DL1 is applied to the first liquid crystal capacitor Clc1through the turned-on first thin film transistor Tr1, and the seconddata voltage applied to the second data line DL2 is applied to thesecond liquid crystal capacitor Clc2 through the turned-on second thinfilm transistor Tr2. The first data voltage has a voltage leveldifferent from a voltage level of the second data voltage. Accordingly,the first liquid crystal capacitor Clc1 is charged with the pixelvoltage different from the pixel voltage charged in the second liquidcrystal capacitor Clc2. For instance, when the first liquid crystalcapacitor Clc1 is charged with the first pixel voltage, the secondliquid crystal capacitor Clc2 may be charged with the second pixelvoltage lower than the first pixel voltage.

Exemplary embodiments of the present invention provide a liquid crystaldisplay panel having at least one pixel with a plurality of slits in itsfirst sub-pixel electrode. These slits widen the side visibility of theliquid crystal display panel due to their parallel arrangement with theliquid crystal alignment directions of the domains of the firstsub-pixel electrode in which they are disposed. The side visibility isfurther enhanced by making the liquid crystal alignment directions ineach of the domains of the first sub-pixel electrode and the liquidcrystal alignment directions in each of the domains of the secondsub-pixel electrode different from each other. When the first sub-pixelelectrode having this slit and liquid crystal alignment directionconfiguration is included in a blue pixel, for example, a differencebetween a gamma value of the blue pixel and a gamma value of a red pixeland between the gamma value of the blue pixel and a gamma value of agreen pixel may be reduced, thereby improving a side visibility of theliquid crystal display panel and a response speed of the blue colorpixel.

Although the exemplary embodiments of the present invention have beendescribed, it is understood that the present invention should not belimited to these exemplary embodiments but various changes andmodifications can be made by one of ordinary skill in the art within thespirit and scope of the present invention as hereinafter claimed.

What is claimed is:
 1. A liquid crystal display panel, comprising: aplurality of pixels, wherein at least one of the pixels includes a firstsub-pixel and a second sub-pixel, wherein the first sub-pixel is chargedwith a first voltage and the second sub-pixel is charged with a secondvoltage that is lower than the first voltage; a first substratecomprising a first sub-pixel electrode of the first sub-pixel and asecond sub-pixel electrode of the second sub-pixel; a first alignmentlayer disposed on the first substrate, wherein the first alignment layeris aligned in a first direction and a second direction in each of thefirst and second sub-pixels; a second substrate facing the firstsubstrate; a second alignment layer disposed on the second substrate,wherein the second alignment layer is aligned in a third direction and afourth direction in each of the first and second sub-pixels to form aplurality of domains in each of the first and second sub-pixels; and aliquid crystal layer disposed between the first alignment layer and thesecond alignment layer, wherein the first sub-pixel electrode includes aplurality of slits and the slits are formed substantially parallel to aliquid crystal alignment direction in each of the domains of the firstsub-pixel electrode, wherein the pixels comprise first, second and thirdpixels, the at least one pixel is the third pixel and an area ratio ofthe second sub-pixel electrode to the first sub-pixel electrode in thethird pixel is larger than an area ratio of a second sub-pixel electrodeto a first sub-pixel electrode in the second pixel.
 2. The liquidcrystal display panel of claim 1, wherein the first pixel is configuredto display a red color, the second pixel is configured to display agreen color, and the third pixel is configured to display a blue color.3. The liquid crystal display panel of claim 2, wherein each of thefirst and second sub-pixel electrodes of the third pixel comprisesfirst, second, third, and fourth domains and the liquid crystalalignment directions of the first to fourth domains of the firstsub-pixel electrode of the third pixel are different from each other,and a liquid crystal alignment direction in each of the first to fourthdomains of the second nib-pixel electrode of the third pixel aredifferent from each other.
 4. The liquid crystal display panel of claim3, wherein the slits comprise first, second, third, and fourth slitsrespectively corresponding to the first, second, third, and fourthdomains of the first sub-pixel electrode of the third pixel, and each ofthe slits is formed substantially parallel to the liquid crystalalignment direction of its corresponding domain.
 5. The liquid crystaldisplay panel of claim 4, wherein the first sub-pixel electrode of thethird pixel comprises a first fringe field area formed along edges ofthe first domain and having an L shape, a second fringe field areaformed along edges of the second domain and having an L shape that isrotated 90 degrees in a counter-clockwise direction from the position ofthe L shape in the first domain, a third fringe field area formed alongedges of the third domain and having an L shape rotated 90 degrees in aclockwise direction from the position of the L shape in the firstdomain, and a fourth fringe area formed along edges of the fourth domainand having an L shape rotated 180 degrees in the counter-clockwisedirection from the position of the L shape in the first domain.
 6. Theliquid crystal display panel of claim 5, wherein the first, second,third, and fourth slits are provided in the first, second, third, andfourth fringe field areas, respectively.
 7. The liquid crystal displaypanel of claim 4, wherein the first sub-pixel electrode of the thirdpixel comprises a first fringe field area formed along an edge of thefirst domain, a second fringe field area formed along an edge of thesecond domain, a third fringe field area formed along an edge of thethird domain, and a fourth fringe field area formed along an edge of thefourth domain, and the first, second, third, and fourth slits are formedalong the edges of the first sub-pixel electrode of the third pixelexcept where the first, second, third, and fourth fringe field areas areformed.
 8. The liquid crystal display panel of claim 2, wherein each ofthe slits has a length of about 10 percent of a width of the firstsub-pixel electrode of the third pixel.
 9. The liquid crystal displaypanel of claim 8, wherein an entire area in which the slits are formedis about 10 percent to about 90 percent of an entire area of the firstsub-pixel electrode of the third pixel.
 10. The liquid crystal displaypanel of claim 2, wherein the first and second pixels each include afirst sub-pixel charged with the first voltage and a second sub-pixelcharged with the second voltage, and a voltage ratio of the secondvoltage to the first voltage in the third pixel is equal to or differentfrom a voltage ratio of the second voltage to the first voltage in eachof the first and second pixels.
 11. The liquid crystal display panel ofclaim 10, wherein the voltage ratio of the second voltage to the firstvoltage in the third pixel is larger than the voltage ratio of thesecond voltage to the first voltage in the second pixel, and the voltageratio of the second voltage to the first voltage in the first pixel isequal to or smaller than the voltage ratio of the second voltage to thefirst voltage in the second pixel.
 12. The liquid crystal display panelof claim 11, wherein the voltage ratio of the second voltage to thefirst voltage in the first pixel is about 0.59 to about 0.845, thevoltage ratio of the second voltage to the first voltage in the secondpixel is about 0.6 to about 0.85, the voltage ratio of the secondvoltage to the first voltage in the third pixel is about 0.61 to about0.9.
 13. The liquid crystal display panel of claim 2, wherein the firstpixel includes first and second sub-pixel electrodes, and the first andsecond sub-pixel electrodes of the first and second pixels are disposedon the first substrate, and the first sub-pixel electrode of each of thefirst, second, and third pixels has a size different from a size of thesecond sub-pixel electrode of each of the first, second, and thirdpixels, respectively, and an area ratio of the second sub-pixelelectrode to the first sub-pixel electrode in the first pixel is equalto or different from the area ratio of the second sub-pixel electrode tothe first sub-pixel electrode in the second pixel.
 14. The liquidcrystal display panel of claim 1, wherein the area ratio of the secondsub-pixel electrode to the first sub-pixel electrode in the third pixelis about 1:1.1 to about 1:3.5, and the area ratio of the secondsub-pixel electrode to the first sub-pixel electrode in the second pixelis about 1:1 to about 1:2.5.
 15. The liquid crystal display panel ofclaim 1, wherein each of the first alignment layer and the secondalignment layer comprises a polymer material in which decomposition,dimerization, or isomerization occurs when irradiated by a light.
 16. Aliquid crystal display panel, comprising: a plurality of pixels, whereinat least one of the pixels includes a first sub-pixel and a secondsub-pixel, wherein the first sub-pixel is charged with a first voltageand the second sub-pixel is charged with a second voltage that is lowerthan the first voltage; a first substrate comprising a first sub-pixelelectrode of the first sub-pixel and a second sub-pixel electrode of thesecond sub-pixel; a second substrate facing the first substrate; and aliquid crystal layer disposed between the first substrate and the secondsubstrate, wherein each of the first sub-pixel electrode and the secondsub-pixel electrode comprises at least two domains having differentliquid crystal alignment directions, and the first sub-pixel electrodeincludes a plurality of slits in at least one of domains and the slitsare formed substantially parallel to the liquid crystal alignmentdirection of the domain in which it is formed, wherein the pixelscomprise a first pixel displaying a red color, a second pixel displayinga green color, and a third pixel displaying a blue color, and the atleast one pixel is the third pixel, wherein the first and second pixelseach include a first sub-pixel charged with the first voltage and asecond sub-pixel charged with the second voltage, and the voltage ratioof the second voltage to the first voltage in the third pixel is largerthan the voltage ratio of the second voltage to the first voltage in thesecond pixel, and the voltage ratio of the second voltage to the firstvoltage in the first pixel is equal to or smaller than the voltage ratioof the second voltage to the first voltage in the second pixel.
 17. Theliquid crystal display panel of claim 16, wherein the first and secondpixels each include first and second sub-pixel electrodes disposed onthe first substrate, and the area ratio of the second sub-pixelelectrode to the first sub-pixel electrode in the third pixel is largerthan the area ratio of the second sub-pixel electrode to the firstsub-pixel electrode in the second pixel.
 18. A liquid crystal displaypanel, comprising: a plurality of pixels, wherein the plurality ofpixels include first and second pixels displaying a different color fromeach other, each of the first and second pixels including a firstsub-pixel and a second sub-pixel, and each of the first and secondsub-pixels includes a plurality of domains, the domains having adifferent liquid crystal alignment direction from each other, whereinthe first sub-pixel of the first pixel includes a first sub-pixelelectrode having a plurality of slits disposed along an edge of thefirst sub-pixel electrode, wherein the second sub-pixel of the firstpixel includes a second sub-pixel electrode, the first sub-pixel and thesecond sub-pixel of the second pixel include a first sub-pixel electrodeand a second sub-pixel electrode, respectively, and an area ratio of thesecond sub-pixel electrode of the first pixel to the first sub-pixelelectrode of the first pixel is greater than an area ratio of the secondsub-pixel electrode of the second pixel to the first sub-pixel electrodeof the second pixel.
 19. The liquid crystal display of claim 18, whereina voltage ratio of a voltage applied to the second sub-pixel electrodeof the first pixel and a voltage applied to the first sub-pixelelectrode of the first pixel is greater than a voltage ratio of avoltage applied to the second sub-pixel electrode of the second pixeland a voltage applied to the first sub-pixel electrode of the secondpixel.